Connecting rod for knuckle joint device and knuckle joint device comprising said rod

ABSTRACT

The connecting rod ( 1 ) for a knuckle joint device with three parallel axes comprises a substantially U-shaped center part ( 2 ), whereby the lower transversal branch ( 3   a ) thereof constitutes a third articulated axis (X 3 ) of a release device and said branch ( 3   a ) is connected at a substantially right angle to the side branches ( 3   b   , 3   c ) and elastic deformation is possible, the side branches extend as far as the upper end thereof by means of segments ( 3   d   ,3   e ) that are bent inwards and are parallel to the transversal branch, whereby said segments ( 3   d   ,3   e ) display torsional elasticity around the geometric axis thereof such that a rotational return movement is possible on the side ranches ( 3   b   ,3   c ) around said geometrical axis and the second axis (X 2 ) of the knuckle joint device.

The invention relates to a connecting rod for a toggle-joint deviceallowing a first component to be held stably in one of two positionsrelative to a second component.

A toggle-joint device such as this comprises a trigger articulated tothe first component about a first axis, the aforementioned connectingrod being articulated, on the one hand, to the second component about asecond axis parallel to the first axis and, on the other hand, to thetrigger about a third axis parallel to the other two. When the triggeris in a stable position, the third axis lies outside the plane of thefirst two axes, and the switch from one stable position to the otherrequires the third axis to cross the plane of the first two axes, withdeformation of the connecting rod. Thrusting means combined with elasticmeans are also provided to cause the trigger to change positionabruptly.

The connecting rod in such a device, while being of a small size bycomparison with the other components, constitutes a significant elementon which the correct operation of the toggle-joint mechanism and itsdurability over time depend.

A toggle-joint device such as this may be used in diverse applicationsrequiring two components to switch from one stable position to anotherstable position relative to one another abruptly. For example, thedevice may be used to control the change in positions of the valves in adifferential hydraulic motor. Such a toggle-joint device may also beused for other applications, particularly in the field of circuitbreakers or electric switches that require an abrupt change in positionof two electric contacts, or in other locking mechanisms.

The object of the invention, is above all, to provide a connecting rodthat makes it possible to simplify the production of a toggle-jointdevice and to ensure that it operates correctly.

According to the invention, the connecting rod has an essentiallyU-shaped central part, the transverse lower branch of which is designedto form the third axis of articulation of the trigger, this lower branchconnecting more or less at right angles to lateral branches capable ofelastic deformation, these lateral branches continuing at their upperend in the form of segments bent outward and parallel to the transversebranch, these segments having elasticity in torsion about theirgeometric axis so as to exert a rotational return force on the lateralbranches about this geometric axis which is coincident with the secondaxis.

The connecting rod according to the invention thus elastically returnsthe trigger to a stable position.

As a preference, the lateral branches have an arched shape;advantageously, these lateral branches form bows lying in a planeorthogonal to the transverse branch.

The outwardly bent segments may be continued by other segments bent inthe opposite direction to the bows; as a preference, these othersegments are bent at right angles, are orthogonal to the transversebranch and are parallel to one another.

The ends of these segments may be set into the second component, and thefreedom of the connecting rod to rotate about the second axis isprovided by the torsional elasticity of the segments directed along thesecond axis.

Also as a preference, the connecting rod is made with longitudinalfibers of high mechanical strength capable of providing the lateralbranches of the connecting rod with tensile and compressive elasticity,these longitudinal fibers being embedded in a plastic matrix capable ofproviding the segments that extend along the second axis with torsionalelasticity.

The longitudinal fibers may be glass fibers or carbon fibers.

The invention also relates to a toggle-joint device comprising aconnecting rod as defined previously.

Apart from the provisions set out hereinabove, the invention consists ina certain number of other dispositions which will be dealt with morefully after with regard to an exemplary embodiment described in detailwith reference to the appended drawings but which is not in any waylimiting.

FIG. 1 of these drawings is a view in perspective of a connecting rodaccording to the invention.

FIG. 2 is a section on a larger scale on II—II of FIG. 1.

FIG. 3 is a schematic view in axial vertical section of a mechanismcomprising a toggle-joint mechanism equipped with the connecting rod ofFIG. 1, the mechanism being depicted in a first stable relative positionof two components.

FIG. 4 shows, in a similar way to FIG. 3, the mechanism in the secondstable position.

Finally, FIG. 5 is an exploded perspective of the elements locatedinside the mechanism of FIGS. 3 and 4.

FIG. 1 shows a connecting rod 1 made of a single piece. This connectingrod 1 comprises an essentially U-shaped central part 2 with a transverselower branch 3 a which is horizontal, according to the depiction of FIG.1, designed to form an axis of articulation X3 of a trigger or trip D(FIGS. 3 to 5) of a toggle-joint device with three axes X1, X2 and X3.

The transverse branch 3 a connects, at each end, to a lateral branch 3b, 3 c essentially at right angles. Each lateral branch 3 b, 3 cpreferably has the shape of an arc of a circle lying in a planeorthogonal to the transverse branch 3 a. The bows of the branches 3 b, 3c are parallel. They may undergo elastic deformation allowing the branch3 a to move parallel to itself, in a direction orthogonal to thistransverse branch 3 a. The lateral branches 3 b, 3 c can thus exerttensile and compressive elastic forces in a direction orthogonal to thebranch 3 a.

The bows 3 b, 3 c are continued, at their opposite end to the branch 3a, by horizontal segments 3 d, 3 e bent outward and parallel to thetransverse branch 3 a. The segments 3 e, 3 d have a certain elasticityin torsion about their geometric axis which constitutes the second axisX2 of the toggle-joint device. The transverse branch 3 a and the lateralbranches 3 b, 3 c can thus oscillate as a unit about the axis X2, beingreturned by the torsional moment developed by the segments 3 d, 3 e.

The segments 3 d, 3 e are continued by other segments 3 f, 3 g bent atright angles in the opposite direction to the bows, parallel to eachother and orthogonal to the branch 3 a. These segments 3 f, 3 g formtabs which may be fixed at their free end into an inset K depictedschematically.

The connecting rod 1 is advantageously made with longitudinal fibers f(FIG. 2) of high mechanical strength. The fibers f are parallel to oneanother. They run along the entire length of the connecting rod,describing the twisty shape of this connecting rod. The fibers f may,for example, be glass fibers or carbon fibers. These fibers f areembedded in a plastic matrix m that has good torsional elasticity.

It can thus be seen that at the segments 3 d, 3 e, the parallel fibers fexhibit practically no resistance in torsion. It is the matrix m whichessentially comes into play for torsional deformations in that region.

By contrast, in the lateral branches 3 b, 3 c, the fibers f work inparallel in respect of the tensile and compressive forces exerted on thebranches 3 b, 3 c.

An example of a toggle-joint device with trigger d is depicted in FIGS.3 to 5.

FIG. 3 shows two components P1 and P2, P1 forming an outer housing andP2 consisting of a cylindrical liner or lantern ring mounted so that itcan slide inside P1.

The toggle-joint device is designed to keep the component P2 in one oftwo stable positions relative to the component P1 and to cause it toswitch abruptly from one stable position to the other.

The toggle-joint device comprises three parallel axes of rotation X1, X2and X3 perpendicular to the plane of FIGS. 3 and 4.

A support 4 fixed to the component P1 is arranged inside the componentP2. The support 4 may consist of two parallel panels 4 a, 4 b (FIG. 5)separated from one another and having a more or less right-trapeziumshaped outline; a long vertical side is adjacent to the interior surfaceof the component P2 and the edge opposite this long vertical side isinclined. The two panels 4 a, 4 b are joined together, at their toppart, by a horizontal transverse bar 5.

The trigger D is arranged between the panels 4 a, 4 b and is articulatedto a shaft 6, the geometric axis of which constitutes the first axis ofrotation X1. This shaft 6 is carried by two bearings provided in thepanels 4 a, 4 b. The axis X1 lies in a diametral plane of the componentP2 more or less at the height of the bar 5. The trigger D has two radialextensions 7 a, 7 b whose thickness (in the direction perpendicular tothe plane of FIGS. 3 and 4) is less than that of the trigger and whichare offset with respect to one another in the direction of the shaft 6.

The connecting rod 1 establishes an articulated connection between thetrigger D and a plate 8 of the component P2. The tabs 3 f, 3 g of theconnecting rod 1 are set into the plate 8. For example, the tabs 3 f, 3g are fixed, for example by bonding, in grooves 8 a constituting theinset K in the plate 8. The segments 3 d, 3 e of the connecting rod 1are perpendicular to the plane of FIG. 1 and their geometric axisdefines the axis X2 of rotation.

Passing through the trip D is a hole 9, the axis of which is parallel tothe shaft 6 situated in the mid-plane of the trip. A hole 9 acommunicating with the hole 9 is provided to the side to make it easierto mount the connecting rod 1. The transverse branch 3 a of theconnecting rod 1 is engaged in the hole 9 and its geometric axis definesthe axis X3 of articulation between the trip D and the connecting rod 1.

Two stable positions of the trigger D are determined by its coming intoabutment respectively with the top face (FIG. 3) and the bottom face(FIG. 4) of the bar 5. The switch from one position to the other is byrotating the trigger D through about 180° relative to the support 4,about X1.

In the stable position of FIG. 3, the lines of the three axes X1, X2 andX3 are at the vertices of a flattened triangle, the axis X3 beingslightly to the left of the plane passing through the axes X1 and X2. X3is between X1 and X2.

To pass through the angular position corresponding to the three pointsX1, X2 and X3 being aligned, the trigger D has to cause slight elasticdeformation of the connecting rod 1 at its branches 3 b, 3 c. Whatactually happens is that the components P1 and P2 in a stable positionare generally in unilateral abutment (via means which have not beendepicted) which, in the case of FIG. 3, prevents an increase in thedistance between X1 and X2, and in the case of FIG. 4 prevents adecrease in the distance between X1 and X2.

In FIG. 4, X3 has crossed to the opposite side of X1 to X2. The lines ofthe three axes X1, X2 and X3 still form a flattened triangle, the axisX3 being slightly to the left with respect to the plane X2-X1.

It can be seen that the components P2 and P1 have changed relativeposition.

Control means are provided to ensure an abrupt change from the positionof FIG. 3 to that of FIG. 4 and vice versa.

These control means comprise a spring 10 arranged around the componentP2, exerting a force along the geometric axis A—A of the assembly.

Triggering means comprise two diametrically opposed upper push-rods 11a, 11 b connected at their base by a circular ring 12, and a lowerpush-rod 13.

The upper push-rods 11 a, 11 b are guided in cutouts 14 of the plate 8,the ring 12 surrounding the component P2. The push-rod 11 a has aninward radial projection 15 a extending over enough distance tocollaborate with the extension 7 b of the trigger D. The spring 10 bearsagainst the ring 12, which itself bears against the lower face of theplate 8.

The lower push-rod 13 has a diametral crossmember 16 passing throughopenings 17 in the wall of the component P2 and which guide the slidingof the push-rod 13. The crossmember 16 is secured to a ring 18surrounding the lower part of the component P2 and bearing axiallyagainst a collar 19 of this component P2. Essentially semi-circularopenings (FIG. 5) exist between the crossmember 16 and the interiorcontour of the ring 18, allowing the passage of the panels 4 a, 4 b.

The crossmember 16 is equipped with a rod 20 coaxial with the componentP2 which passes through a central opening in the end wall of thecomponent P1.

The crossmember 16 comprises, on one side, an upward projection 16 acapable of collaborating with the extension 7 a of the trigger in theposition of FIG. 4.

This being the case, the way in which the toggle-joint device works isas follows.

It will be assumed that the component P1 is kept stationary, but theexplanations which follow remain valid if this component P1 is given amotion which is transmitted to the component P2.

Starting out from the configuration depicted in FIG. 3, whichcorresponds to a first stable position, all that is required is forpressure to be exerted on the push-rods 11 a, 11 b, for example using acomponent M1 capping these two push-rods, to cause the push-rods 11 a,11 b to move downward, compressing the spring 10 until the projection 15a begins to act on the extension 7 b of the trigger.

The latter is then made to rotate in a clockwise direction about theaxis X1.

Passage through the position in which the lines of the axes X2, X1 andX3 are aligned takes place at the expense of elastic deformation of thebows 3 b, 3 c and of a rotation of limited amplitude about the axis X2.

Once the aligned position has been passed, the spring 10 relaxes andcauses the trigger D to turn abruptly, the extension 7 b of whichtrigger comes to bear under the stop 5, the component P2 then occupyingthe second stable position illustrated in FIG. 4 relative to thecomponent P1.

To return to the position illustrated in FIG. 3 all that is required isfor the rod 20, for example equipped with a button M2, to be pressed inorder to cause the trigger D to trip by action of the projection 16 aagainst the extension 7 a.

As already explained, the connecting rod 1 has a two-fold elasticfunction, firstly in tension and compression for locking the system,through action of the branches 3 b, 3 c, and secondly through thetorsional elasticity of the segments 3 e, 3 d keeping the assembly inthe locked position.

Such a toggle-joint device may be suited to any mechanism requiring acomponent P2 to pass from a first stable position to a second stableposition relative to a component P1.

What is claimed is:
 1. A toggle joint device disposed between a firstcomponent and a second component, wherein one of said first and secondcomponents is moveable with respect to the other, said toggle jointdevice comprising: a trigger connected to the first component at alocation of a first axis, wherein said trigger is rotatable about saidfirst axis; a thrusting means and an elastic element positioned to causethe trigger to change position abruptly; a connecting rod connected tothe second component at a location of a second axis and connected to thetrigger at a location of a third axis, wherein the first axis, secondaxis and third axis are parallel to one another, and wherein saidconnecting rod is articulated about said second axis and said thirdaxis, said connecting rod comprising an essentially U-shaped centralpart including a transverse lower branch that forms the third axis, saidlower branch connecting at substantially right angles to lateralbranches forming bows lying in a plane orthogonal to the transversebranch, said bows continuing in the form of segments bent outward andparallel to the transverse branch, said segments having a geometric axiscoincident with the second axis, and said segments having elasticity intorsion about the geometric axis so as to exert a rotational returnforce on the lateral branches about the geometric axis; and wherein:said toggle-joint device provides a first stable position of the firstand second components and a second stable position of the first andsecond components; the first axis, second axis and third axis aredisposed at vertices of a flattened triangle when the first and secondcomponents are positioned in either of the two stable positions; thetoggle-joint device passes through an angular position corresponding tothe first axis, second axis and third axis being positioned in the sameplane in order to move the first and second components from one of thestable positions to another of the stable positions; and moving thefirst and second components from one of the stable positions to anotherof the stable positions causes elastic deformation of the connectingrod.
 2. A toggle-joint device according to claim 1, wherein the segmentsextend to form other segments bent at right angles in an oppositedirection to the bows, wherein the ends of the other segments are setfixed into the second component, and wherein freedom of the connectingrod to rotate about the second axis is provided by torsional elasticityof the segments directed along the second axis.
 3. A toggle joint deviceaccording to claim 2, wherein the other segments are orthogonal to thetransverse branch and are parallel to one another.
 4. A toggle jointdevice according to claim 3, wherein the connecting rod is made withlongitudinal fibers of high mechanical strength capable of providing thelateral branches of the connecting rod with tensile and compressiveelasticity, wherein the longitudinal fibers are embedded in a plasticmatrix capable of providing the segments that extend along the secondaxis with torsional elasticity.
 5. A toggle joint device according toclaim 4, wherein the longitudinal fibers comprise glass fibers or carbonfibers.
 6. A toggle joint device according to claim 2, wherein theconnecting rod is made with longitudinal fibers of high mechanicalstrength capable of providing the lateral branches of the connecting rodwith tensile and compressive elasticity, wherein the longitudinal fibersare embedded in a plastic matrix capable of providing the segments thatextend along the second axis with torsional elasticity.
 7. A togglejoint device according to claim 6, wherein the longitudinal fiberscomprise glass fibers or carbon fibers.
 8. A toggle joint deviceaccording to claim 1, wherein the other segments are orthogonal to thetransverse branch and are parallel to one another.
 9. A toggle jointdevice according to claim 8, wherein the connecting rod is made withlongitudinal fibers of high mechanical strength capable of providing thelateral branches of the connecting rod with tensile and compressiveelasticity, wherein the longitudinal fibers are embedded in a plasticmatrix capable of providing the segments that extend along the secondaxis with torsional elasticity.
 10. A toggle joint device according toclaim 6, wherein the longitudinal fibers comprise glass fibers or carbonfibers.
 11. A toggle joint device according to claim 1, wherein theconnecting rod is made with longitudinal fibers of high mechanicalstrength capable of providing the lateral branches of the connecting rodwith tensile and compressive elasticity, wherein the longitudinal fibersare embedded in a plastic matrix capable of providing the segments thatextend along the second axis with torsional elasticity.
 12. A togglejoint device according to claim 11, wherein the longitudinal fiberscomprise glass fibers or carbon fibers.
 13. A connecting rod for atoggle-joint device, said toggle-joint device being disposed betweenfirst and second components, one of said first and second componentsbeing moveable with respect to the other, said toggle-joint deviceproviding a first stable position of the first and second components anda second stable position of the first and second components, saidtoggle-joint device including a trigger that is connected to the firstcomponent at a location of a first axis and is rotatable about saidfirst axis, said toggle-joint device including a thrusting means and anelastic element positioned to cause the trigger to change positionabruptly, wherein: the connecting rod is connected to the secondcomponent at a location of a second axis and is connected to the triggerat a location of a third axis, wherein the first axis, second axis andthird axis are parallel to one another. the connecting rod isarticulated about said second axis and said third axis; the connectingrod comprises an essentially U-shaped central part including atransverse lower branch that forms the third axis, wherein said lowerbranch connects at substantially right angles to lateral branchesforming bows lying in a plane orthogonal to the transverse branch,wherein said bows continue in the form of segments bent outward andparallel to the transverse branch, wherein said segments have ageometric axis coincident with the second axis, and wherein saidsegments have elasticity in torsion about the geometric axis so as toexert a rotational return force on the lateral branches about thegeometric axis; the first axis, second axis and third axis are disposedat vertices of a flattened triangle when the first and second componentsare positioned in either of the two stable positions; the toggle-jointdevice passes through an angular position corresponding to the firstaxis, second axis and third axis being positioned in the same plane inorder to move the first and second components from one of the stablepositions to another of the stable positions; the connecting rodexperiences elastic deformation when moving the first and secondcomponents from one of the first and second stable positions to anotherof the first and second stable positions; and the connecting rod is madewith longitudinal fibers of high mechanical strength capable ofproviding the lateral branches of the connecting rod with tensile andcompressive elasticity, wherein the longitudinal fibers are embedded ina plastic matrix capable of providing the segments that extend along thesecond axis with torsional elasticity.
 14. The connecting rod of claim13, wherein the segments extend to form other segments bent at rightangles in an opposite direction to the bows, wherein the ends of theother segments are set fixed into the second component, and whereinfreedom of the connecting rod to rotate about the second axis isprovided by torsional elasticity of the segments directed along thesecond axis.
 15. The connecting rod of claim 14, wherein the othersegments are orthogonal to the transverse branch and are parallel to oneanother.
 16. The connecting rod of claim 15, wherein the longitudinalfibers comprise glass fibers or carbon fibers.
 17. The connecting rod ofclaim 14, wherein the longitudinal fibers comprise glass fibers orcarbon fibers.
 18. The connecting rod of claim 13, wherein thelongitudinal fibers comprise glass fibers or carbon fibers.